1. Field of the Invention
The present invention relates to a distortion inspection apparatus for glass plate and, more particularly, to an apparatus for optical distortion inspection of reinforced curved glass or laminated curved glass such as a windshield glass of a vehicle.
2. Description of the Prior Art
A so-called reinforced curved glass or laminated curved glass in which a plurality of glass sheets are adhered by means of resin layers such as polyvinyl butyral is used as windshield glass of an automobile. In such glass windshields, optical distortions or uneven surfaces can occur. When the distortion or abraded surface is considerable, the field of vision can be undesirably distorted according to the angle of sight.
Conventionally, an examiner utilizing a light and dark stripe pattern (e.g., a zebra-like pattern) from a distant position visually inspects a completed laminated glass windshield and thus performs organoleptic inspection of the the stripe pattern distortion while the viewing angle (azimuth) of the windshield is changed, thereby examining or discriminating the quality of the laminated glass. However, in such a visual inspection, quantitative standardization cannot be obtained, and differences among examiners prevent uniform inspection quality.